Those bits fit for electric screwdrivers, hand screwdrivers, electric drills, air drills and so forth.
PH0 is suitable for small appliances and precision apparatuses;
PH1 is suitable for major and small appliances;
PH2 is suitable for household screws and major appliances.
Do not turn the screws with unmatched size, in case get both screw and bit damaged.Please allow a bit manual measuring errors.